The objective of this project is to define the regulation of contractile protein activity in brain and specifically as they relate to release ad uptake of neurotransmitters by synaptosomal enriched fractions. Regulatory brain proteins respond to calcium in a fashion similar to regulatory protein of muscle. In brain, however, they are separat%d, myosin on synaptic vesicles bind actin complex on synaptosomal membranes and their association, apparently permits contractile effect on synaptic vesicles with release of neurotransmitters. Like in muscle, such brain synaptosomal activity is stimulated by magnesium-ATP when calcium is present, and it is inhibited when calcium is chelated by EGTA. We propose to study the relaxing (regulatory) proteins by determining their biochemical activity, localize these proteins within the synaptosomal structures by preparing ferritin conjugated antisera against each of these proteins, and finally determine their involvement in the mechanism that produces uptake and release of neurotransmitters in brain. Attempts will be made to correlate structure and function of brain cntractile proteins with clinical findings in neurological disorders. BIBLIOGRAPHIC REFERENCES: Puszkin, S., Kochwa, S., Puszkin, E., Rosenfield, R.E., J. Biol. Chem. 250,2085,1975. Puszkin, S., Bloom,W., Kochwa, S., Rosenfield, R.E., Fed. Procc. 34,240, l975.